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2021-07-26nbd/server: Mark variable unused in nbd_negotiate_meta_queriesRichard Henderson
From clang-13: nbd/server.c:976:22: error: variable 'bitmaps' set but not used \ [-Werror,-Wunused-but-set-variable] which is incorrect; see //bugs.llvm.org/show_bug.cgi?id=3888. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-06-18nbd/client-connection: add option for non-blocking connection attemptVladimir Sementsov-Ogievskiy
We'll need a possibility of non-blocking nbd_co_establish_connection(), so that it returns immediately, and it returns success only if a connections was previously established in background. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-30-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: return only one io channelVladimir Sementsov-Ogievskiy
block/nbd doesn't need underlying sioc channel anymore. So, we can update nbd/client-connection interface to return only one top-most io channel, which is more straight forward. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-27-vsementsov@virtuozzo.com> [eblake: squash in Vladimir's fixes for uninit usage caught by clang] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: shutdown connection on releaseVladimir Sementsov-Ogievskiy
Now, when a thread can do negotiation and retry, it may run relatively long. We need a mechanism to stop it, when the user is not interested in a result any more. So, on nbd_client_connection_release() let's shutdown the socket, and do not retry connection if thread is detached. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-22-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: implement connection retryVladimir Sementsov-Ogievskiy
Add an option for a thread to retry connecting until it succeeds. We'll use nbd/client-connection both for reconnect and for initial connection in nbd_open(), so we need a possibility to use same NBDClientConnection instance to connect once in nbd_open() and then use retry semantics for reconnect. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-21-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: grammar tweak] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: add possibility of negotiationVladimir Sementsov-Ogievskiy
Add arguments and logic to support nbd negotiation in the same thread after successful connection. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-20-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd/client-connection: use QEMU_LOCK_GUARDVladimir Sementsov-Ogievskiy
We don't update connect_thread_func() to use QEMU_LOCK_GUARD, as it will get more complex critical sections logic in further commit, where QEMU_LOCK_GUARD doesn't help. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210610100802.5888-19-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-18nbd: move connection code from block/nbd to nbd/client-connectionVladimir Sementsov-Ogievskiy
We now have bs-independent connection API, which consists of four functions: nbd_client_connection_new() nbd_client_connection_release() nbd_co_establish_connection() nbd_co_establish_connection_cancel() Move them to a separate file together with NBDClientConnection structure which becomes private to the new API. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210610100802.5888-18-vsementsov@virtuozzo.com> [eblake: comment tweaks] Signed-off-by: Eric Blake <eblake@redhat.com>
2021-06-02Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell
Block layer patches - NBD server: Fix crashes related to switching between AioContexts - file-posix: Workaround for discard/write_zeroes on buggy filesystems - Follow-up fixes for the reopen vs. permission changes - quorum: Fix error handling for flush - block-copy: Refactor copy_range handling - docs: Describe how to use 'null-co' block driver # gpg: Signature made Wed 02 Jun 2021 14:44:15 BST # gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6 # gpg: issuer "kwolf@redhat.com" # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full] # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: docs/secure-coding-practices: Describe how to use 'null-co' block driver block-copy: refactor copy_range handling block-copy: fix block_copy_task_entry() progress update nbd/server: Use drained block ops to quiesce the server block-backend: add drained_poll block: improve permission conflict error message block: simplify bdrv_child_user_desc() block/vvfat: inherit child_vvfat_qcow from child_of_bds block: improve bdrv_child_get_parent_desc() block-backend: improve blk_root_get_parent_desc() block: document child argument of bdrv_attach_child_common() block/file-posix: Try other fallbacks after invalid FALLOC_FL_ZERO_RANGE block/file-posix: Fix problem with fallocate(PUNCH_HOLE) on GPFS block: drop BlockBackendRootState::read_only block: drop BlockDriverState::read_only block: consistently use bdrv_is_read_only() block/vvfat: fix vvfat_child_perm crash block/vvfat: child_vvfat_qcow: add .get_parent_aio_context, fix crash qemu-io-cmds: assert that we don't have .perm requested in no-blk case block/quorum: Provide .bdrv_co_flush instead of .bdrv_co_flush_to_disk Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-06-02nbd/server: Use drained block ops to quiesce the serverSergio Lopez
Before switching between AioContexts we need to make sure that we're fully quiesced ("nb_requests == 0" for every client) when entering the drained section. To do this, we set "quiescing = true" for every client on ".drained_begin" to prevent new coroutines from being created, and check if "nb_requests == 0" on ".drained_poll". Finally, once we're exiting the drained section, on ".drained_end" we set "quiescing = false" and call "nbd_client_receive_next_request()" to resume the processing of new requests. With these changes, "blk_aio_attach()" and "blk_aio_detach()" can be reverted to be as simple as they were before f148ae7d36. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1960137 Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Sergio Lopez <slp@redhat.com> Message-Id: <20210602060552.17433-3-slp@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-06-02docs: fix references to docs/devel/tracing.rstStefano Garzarella
Commit e50caf4a5c ("tracing: convert documentation to rST") converted docs/devel/tracing.txt to docs/devel/tracing.rst. We still have several references to the old file, so let's fix them with the following command: sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt) Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210517151702.109066-2-sgarzare@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-03-08nbd: server: Report holes for raw imagesNir Soffer
When querying image extents for raw image, qemu-nbd reports holes as zero: $ qemu-nbd -t -r -f raw empty-6g.raw $ qemu-img map --output json nbd://localhost [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": true, "offset": 0}] $ qemu-img map --output json empty-6g.raw [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}] Turns out that qemu-img map reports a hole based on BDRV_BLOCK_DATA, but nbd server reports a hole based on BDRV_BLOCK_ALLOCATED. The NBD protocol says: NBD_STATE_HOLE (bit 0): if set, the block represents a hole (and future writes to that area may cause fragmentation or encounter an NBD_ENOSPC error); if clear, the block is allocated or the server could not otherwise determine its status. qemu-img manual says: whether the sectors contain actual data or not (boolean field data; if false, the sectors are either unallocated or stored as optimized all-zero clusters); To me, data=false looks compatible with NBD_STATE_HOLE. From user point of view, getting same results from qemu-nbd and qemu-img is more important than being more correct about allocation status. Changing nbd server to report holes using BDRV_BLOCK_DATA makes qemu-nbd results compatible with qemu-img map: $ qemu-img map --output json nbd://localhost [{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}] Signed-off-by: Nir Soffer <nsoffer@redhat.com> Message-Id: <20210219160752.1826830-1-nsoffer@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2021-01-20nbd/server: Quiesce coroutines on context switchSergio Lopez
When switching between AIO contexts we need to me make sure that both recv_coroutine and send_coroutine are not scheduled to run. Otherwise, QEMU may crash while attaching the new context with an error like this one: aio_co_schedule: Co-routine was already scheduled in 'aio_co_schedule' To achieve this we need a local implementation of 'qio_channel_readv_all_eof' named 'nbd_read_eof' (a trick already done by 'nbd/client.c') that allows us to interrupt the operation and to know when recv_coroutine is yielding. With this in place, we delegate detaching the AIO context to the owning context with a BH ('nbd_aio_detach_bh') scheduled using 'aio_wait_bh_oneshot'. This BH signals that we need to quiesce the channel by setting 'client->quiescing' to 'true', and either waits for the coroutine to finish using AIO_WAIT_WHILE or, if it's yielding in 'nbd_read_eof', actively enters the coroutine to interrupt it. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1900326 Signed-off-by: Sergio Lopez <slp@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20201214170519.223781-4-slp@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-11-17Merge remote-tracking branch ↵Peter Maydell
'remotes/huth-gitlab/tags/pull-request-2020-11-17' into staging * Fixes for compiling on Haiku, and add Haiku VM for compile-testing * Update NetBSD VM to version 9.1 * Misc fixes (e.g. categorize some devices) # gpg: Signature made Tue 17 Nov 2020 09:20:31 GMT # gpg: using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5 # gpg: issuer "thuth@redhat.com" # gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full] # gpg: aka "Thomas Huth <thuth@redhat.com>" [full] # gpg: aka "Thomas Huth <huth@tuxfamily.org>" [full] # gpg: aka "Thomas Huth <th.huth@posteo.de>" [unknown] # Primary key fingerprint: 27B8 8847 EEE0 2501 18F3 EAB9 2ED9 D774 FE70 2DB5 * remotes/huth-gitlab/tags/pull-request-2020-11-17: max111x: put it into the 'misc' category nand: put it into the 'storage' category ads7846: put it into the 'input' category ssd0323: put it into the 'display' category gitlab-ci: Use $CI_REGISTRY instead of hard-coding registry.gitlab.com target/microblaze: Fix possible array out of bounds in mmu_write() tests/vm: update NetBSD to 9.1 tests/vm: Add Haiku test based on their vagrant images configure: Add a proper check for sys/ioccom.h and use it in tpm_ioctl.h configure: Do not build pc-bios/optionrom on Haiku configure: Fix the _BSD_SOURCE define for the Haiku build qemu/bswap: Remove unused qemu_bswap_len() Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-11-17configure: Add a proper check for sys/ioccom.h and use it in tpm_ioctl.hThomas Huth
On Solaris and Haiku, the _IO() macros are defined in <sys/ioccom.h>. Add a proper check for this header to our build system, and make sure to include the header in tpm_ioctl.h to fix a build failure on Solaris and Haiku. Message-Id: <20201115152317.42752-1-thuth@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-11-16nbd: Silence Coverity false positiveEric Blake
Coverity noticed (CID 1436125) that we check the return value of nbd_extent_array_add in most places, but not at the end of bitmap_to_extents(). The return value exists to break loops before a future iteration, so there is nothing to check if we are already done iterating. Adding a cast to void, plus a comment why, pacifies Coverity. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201111163510.713855-1-eblake@redhat.com> [eblake: Prefer cast to void over odd && usage] Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2020-10-30nbd: Add 'qemu-nbd -A' to expose allocation depthEric Blake
Allow the server to expose an additional metacontext to be requested by savvy clients. qemu-nbd adds a new option -A to expose the qemu:allocation-depth metacontext through NBD_CMD_BLOCK_STATUS; this can also be set via QMP when using block-export-add. qemu as client is hacked into viewing the key aspects of this new context by abusing the already-experimental x-dirty-bitmap option to collapse all depths greater than 2, which results in a tri-state value visible in the output of 'qemu-img map --output=json' (yes, that means x-dirty-bitmap is now a bit of a misnomer, but I didn't feel like renaming it as it would introduce a needless break of back-compat, even though we make no compat guarantees with x- members): unallocated (depth 0) => "zero":false, "data":true local (depth 1) => "zero":false, "data":false backing (depth 2+) => "zero":true, "data":true libnbd as client is probably a nicer way to get at the information without having to decipher such hacks in qemu as client. ;) Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-11-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30nbd: Add new qemu:allocation-depth metadata contextEric Blake
'qemu-img map' provides a way to determine which extents of an image come from the top layer vs. inherited from a backing chain. This is useful information worth exposing over NBD. There is a proposal to add a QMP command block-dirty-bitmap-populate which can create a dirty bitmap that reflects allocation information, at which point the qemu:dirty-bitmap:NAME metadata context can expose that information via the creation of a temporary bitmap, but we can shorten the effort by adding a new qemu:allocation-depth metadata context that does the same thing without an intermediate bitmap (this patch does not eliminate the need for that proposal, as it will have other uses as well). While documenting things, remember that although the NBD protocol has NBD_OPT_SET_META_CONTEXT, the rest of its documentation refers to 'metadata context', which is a more apt description of what is actually being used by NBD_CMD_BLOCK_STATUS: the user is requesting metadata by passing one or more context names. So I also touched up some existing wording to prefer the term 'metadata context' where it makes sense. Note that this patch does not actually enable any way to request a server to enable this context; that will come in the next patch. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-10-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30nbd: Allow export of multiple bitmaps for one deviceEric Blake
With this, 'qemu-nbd -B b0 -B b1 -f qcow2 img.qcow2' can let you sniff out multiple bitmaps from one server. qemu-img as client can still only read one bitmap per client connection, but other NBD clients (hello libnbd) can now read multiple bitmaps in a single pass. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201027050556.269064-8-eblake@redhat.com>
2020-10-30nbd: Refactor counting of metadata contextsEric Blake
Rather than open-code the count of negotiated contexts at several sites, embed it directly into the struct. This will make it easier for upcoming commits to support even more simultaneous contexts. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-7-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-10-30nbd: Simplify qemu bitmap context nameEric Blake
Each dirty bitmap already knows its name; by reducing the scope of the places where we construct "qemu:dirty-bitmap:NAME" strings, tracking the name is more localized, and there are fewer per-export fields to worry about. This in turn will make it easier for an upcoming patch to export more than one bitmap at once. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201027050556.269064-6-eblake@redhat.com>
2020-10-30nbd: Update qapi to support exporting multiple bitmapsEric Blake
Since 'block-export-add' is new to 5.2, we can still tweak the interface; there, allowing 'bitmaps':['str'] is nicer than 'bitmap':'str'. This wires up the qapi and qemu-nbd changes to permit passing multiple bitmaps as distinct metadata contexts that the NBD client may request, but the actual support for more than one will require a further patch to the server. Note that there are no changes made to the existing deprecated 'nbd-server-add' command; this required splitting the QAPI type BlockExportOptionsNbd, which fortunately does not affect QMP introspection. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20201027050556.269064-5-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2020-10-23block/export: add iothread and fixed-iothread optionsStefan Hajnoczi
Make it possible to specify the iothread where the export will run. By default the block node can be moved to other AioContexts later and the export will follow. The fixed-iothread option forces strict behavior that prevents changing AioContext while the export is active. See the QAPI docs for details. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20200929125516.186715-5-stefanha@redhat.com [Fix stray '#' character in block-export.json and add missing "(since: 5.2)" as suggested by Eric Blake. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-23block: move block exports to libblockdevStefan Hajnoczi
Block exports are used by softmmu, qemu-storage-daemon, and qemu-nbd. They are not used by other programs and are not otherwise needed in libblock. Undo the recent move of blockdev-nbd.c from blockdev_ss into block_ss. Since bdrv_close_all() (libblock) calls blk_exp_close_all() (libblockdev) a stub function is required.. Make qemu-nbd.c use signal handling utility functions instead of duplicating the code. This helps because os-posix.c is in libblockdev and it depends on a qemu_system_killed() symbol that qemu-nbd.c lacks. Once we use the signal handling utility functions we also end up providing the necessary symbol. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20200929125516.186715-4-stefanha@redhat.com [Fixed s/ndb/nbd/ typo in commit description as suggested by Eric Blake --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-09nbd: Simplify meta-context parsingEric Blake
We had a premature optimization of trying to read as little from the wire as possible while handling NBD_OPT_SET_META_CONTEXT in phases. But in reality, we HAVE to read the entire string from the client before we can get to the next command, and it is easier to just read it all at once than it is to read it in pieces. And once we do that, several functions end up no longer performing I/O, so they can drop length and errp parameters, and just return a bool instead of modifying through a pointer. Our iotests still pass; I also checked that libnbd's testsuite (which covers more corner cases of odd meta context requests) still passes. There are cases where the sequence of trace messages produced differs (for example, when no bitmap is exported, a query for "qemu:" now produces two trace lines instead of one), but trace points are for debug and have no effect on what the client sees. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200930121105.667049-4-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [eblake: enhance commit message] Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-09nbd/server: Reject embedded NUL in NBD stringsEric Blake
The NBD spec is clear that any string sent from the client must not contain embedded NUL characters. If the client passes "a\0", we should reject that option request rather than act on "a". Testing this is not possible with a compliant client, but I was able to use gdb to coerce libnbd into temporarily behaving as such a client. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200930121105.667049-3-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-09nbd: silence maybe-uninitialized warningsChristian Borntraeger
gcc 10 from Fedora 32 gives me: Compiling C object libblock.fa.p/nbd_server.c.o ../nbd/server.c: In function ‘nbd_co_client_start’: ../nbd/server.c:625:14: error: ‘namelen’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 625 | rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 626 | errp); | ~~~~~ ../nbd/server.c:564:14: note: ‘namelen’ was declared here 564 | uint32_t namelen; | ^~~~~~~ cc1: all warnings being treated as errors As I cannot see how this can happen, let uns silence the warning. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Message-Id: <20200930155859.303148-3-borntraeger@de.ibm.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-02nbd: Merge nbd_export_new() and nbd_export_create()Kevin Wolf
There is no real reason any more why nbd_export_new() and nbd_export_create() should be separate functions. The latter only performs a few checks before it calls the former. What makes the current state stand out is that it's the only function in BlockExportDriver that is not a static function inside nbd/server.c, but a small wrapper in blockdev-nbd.c that then calls back into nbd/server.c for the real functionality. Move all the checks to nbd/server.c and make the resulting function static to improve readability. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-27-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move writable to BlockExportOptionsKevin Wolf
The 'writable' option is a basic option that will probably be applicable to most if not all export types that we will implement. Move it from NBD to the generic BlockExport layer. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-26-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Create BlockBackend in blk_exp_add()Kevin Wolf
Every export type will need a BlockBackend, so creating it centrally in blk_exp_add() instead of the .create driver callback avoids duplication. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-24-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move blk to BlockExportKevin Wolf
Every block export has a BlockBackend representing the disk that is exported. It should live in BlockExport therefore. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-23-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add block-export-delKevin Wolf
Implement a new QMP command block-export-del and make nbd-server-remove a wrapper around it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-21-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move strong user reference to block_exportsKevin Wolf
The reference owned by the user/monitor that is created when adding the export and dropped when removing it was tied to the 'exports' list in nbd/server.c. Every block export will have a user reference, so move it to the block export level and tie it to the 'block_exports' list in block/export/export.c instead. This is necessary for introducing a QMP command for removing exports. Note that exports are present in block_exports even after the user has requested shutdown. This is different from NBD's exports where exports are immediately removed on a shutdown request, even if they are still in the process of shutting down. In order to avoid that the user still interacts with an export that is shutting down (and possibly removes it a second time), we need to remember if the user actually still owns it. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-20-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add blk_exp_close_all(_type)Kevin Wolf
This adds a function to shut down all block exports, and another one to shut down the block exports of a single type. The latter is used for now when stopping the NBD server. As soon as we implement support for multiple NBD servers, we'll need a per-server list of exports and it will be replaced by a function using that. As a side effect, the BlockExport layer has a list tracking all existing exports now. closed_exports loses its only user and can go away. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-18-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Allocate BlockExport in blk_exp_add()Kevin Wolf
Instead of letting the driver allocate and return the BlockExport object, allocate it already in blk_exp_add() and pass it. This allows us to initialise the generic part before calling into the driver so that the driver can just use these values instead of having to parse the options a second time. For symmetry, move freeing the BlockExport to blk_exp_unref(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-17-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move AioContext from NBDExport to BlockExportKevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-15-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Move refcount from NBDExport to BlockExportKevin Wolf
Having a refcount makes sense for all types of block exports. It is also a prerequisite for keeping a list of all exports at the BlockExport level. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-14-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02nbd/server: Simplify export shutdownKevin Wolf
Closing export is somewhat convoluted because nbd_export_close() and nbd_export_put() call each other and the ways they actually end up being nested is not necessarily obvious. However, it is not really necessary to call nbd_export_close() from nbd_export_put() when putting the last reference because it only does three things: 1. Close all clients. We're going to refcount 0 and all clients hold a reference, so we know there is no active client any more. 2. Close the user reference (represented by exp->name being non-NULL). The same argument applies: If the export were still named, we would still have a reference. 3. Freeing exp->description. This is really cleanup work to be done when the export is finally freed. There is no reason to already clear it while clients are still in the process of shutting down. So after moving the cleanup of exp->description, the code can be simplified so that only nbd_export_close() calls nbd_export_put(), but never the other way around. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200924152717.287415-13-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02nbd: Remove NBDExport.close callbackKevin Wolf
The export close callback is unused by the built-in NBD server. qemu-nbd uses it only during shutdown to wait for the unrefed export to actually go away. It can just use nbd_export_close_all() instead and do without the callback. This removes the close callback from nbd_export_new() and makes both callers of it more similar. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200924152717.287415-11-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Remove magic from block-export-addKevin Wolf
nbd-server-add tries to be convenient and adds two questionable features that we don't want to share in block-export-add, even for NBD exports: 1. When requesting a writable export of a read-only device, the export is silently downgraded to read-only. This should be an error in the context of block-export-add. 2. When using a BlockBackend name, unplugging the device from the guest will automatically stop the NBD server, too. This may sometimes be what you want, but it could also be very surprising. Let's keep things explicit with block-export-add. If the user wants to stop the export, they should tell us so. Move these things into the nbd-server-add QMP command handler so that they apply only there. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-8-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02qemu-nbd: Use raw block driver for --offsetKevin Wolf
Instead of implementing qemu-nbd --offset in the NBD code, just put a raw block node with the requested offset on top of the user image and rely on that doing the job. This does not only simplify the nbd_export_new() interface and bring it closer to the set of options that the nbd-server-add QMP command offers, but in fact it also eliminates a potential source for bugs in the NBD code which previously had to add the offset manually in all relevant places. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200924152717.287415-7-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02block/export: Add BlockExport infrastructure and block-export-addKevin Wolf
We want to have a common set of commands for all types of block exports. Currently, this is only NBD, but we're going to add more types. This patch adds the basic BlockExport and BlockExportDriver structs and a QMP command block-export-add that creates a new export based on the given BlockExportOptions. qmp_nbd_server_add() becomes a wrapper around qmp_block_export_add(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200924152717.287415-5-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02nbd: Remove unused nbd_export_get_blockdev()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200924152717.287415-2-kwolf@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07nbd: Use CAF when looking for dirty bitmapMax Reitz
When looking for a dirty bitmap to share, we should handle filters by just including them in the search (so they do not break backing chains). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-08-21meson: convert blockMarc-André Lureau
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-08-21trace: switch position of headers to what Meson requiresPaolo Bonzini
Meson doesn't enjoy the same flexibility we have with Make in choosing the include path. In particular the tracing headers are using $(build_root)/$(<D). In order to keep the include directives unchanged, the simplest solution is to generate headers with patterns like "trace/trace-audio.h" and place forwarding headers in the source tree such that for example "audio/trace.h" includes "trace/trace-audio.h". This patch is too ugly to be applied to the Makefiles now. It's only a way to separate the changes to the tracing header files from the Meson rewrite of the tracing logic. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-28nbd: Fix large trim/zero requestsEric Blake
Although qemu as NBD client limits requests to <2G, the NBD protocol allows clients to send requests almost all the way up to 4G. But because our block layer is not yet 64-bit clean, we accidentally wrap such requests into a negative size, and fail with EIO instead of performing the intended operation. The bug is visible in modern systems with something as simple as: $ qemu-img create -f qcow2 /tmp/image.img 5G $ sudo qemu-nbd --connect=/dev/nbd0 /tmp/image.img $ sudo blkdiscard /dev/nbd0 or with user-space only: $ truncate --size=3G file $ qemu-nbd -f raw file $ nbdsh -u nbd://localhost:10809 -c 'h.trim(3*1024*1024*1024,0)' Although both blk_co_pdiscard and blk_pwrite_zeroes currently return 0 on success, this is also a good time to fix our code to a more robust paradigm that treats all non-negative values as success. Alas, our iotests do not currently make it easy to add external dependencies on blkdiscard or nbdsh, so we have to rely on manual testing for now. This patch can be reverted when we later improve the overall block layer to be 64-bit clean, but for now, a minimal fix was deemed less risky prior to release. CC: qemu-stable@nongnu.org Fixes: 1f4d6d18ed Fixes: 1c6c4bb7f0 Fixes: https://github.com/systemd/systemd/issues/16242 Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200722212231.535072-1-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [eblake: rework success tests to use >=0]
2020-07-17nbd: make nbd_export_close_all() synchronousVladimir Sementsov-Ogievskiy
Consider nbd_export_close_all(). The call-stack looks like this: nbd_export_close_all() -> nbd_export_close -> call client_close() for each client. client_close() doesn't guarantee that client is closed: nbd_trip() keeps reference to it. So, nbd_export_close_all() just reduce reference counter on export and removes it from the list, but doesn't guarantee that nbd_trip() finished neither export actually removed. Let's wait for all exports actually removed. Without this fix, the following crash is possible: - export bitmap through internal Qemu NBD server - connect a client - shutdown Qemu On shutdown nbd_export_close_all is called, but it actually don't wait for nbd_trip() to finish and to release its references. So, export is not release, and exported bitmap remains busy, and on try to remove the bitmap (which is part of bdrv_close()) the assertion fails: bdrv_release_dirty_bitmap_locked: Assertion `!bdrv_dirty_bitmap_busy(bitmap)' failed Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200714162234.13113-2-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-10nbd: Use ERRP_GUARD()Vladimir Sementsov-Ogievskiy
If we want to check error after errp-function call, we need to introduce local_err and then propagate it to errp. Instead, use the ERRP_GUARD() macro, benefits are: 1. No need of explicit error_propagate call 2. No need of explicit local_err variable: use errp directly 3. ERRP_GUARD() leaves errp as is if it's not NULL or &error_fatal, this means that we don't break error_abort (we'll abort on error_set, not on error_propagate) If we want to add some info to errp (by error_prepend() or error_append_hint()), we must use the ERRP_GUARD() macro. Otherwise, this info will not be added when errp == &error_fatal (the program will exit prior to the error_append_hint() or error_prepend() call). Fix several such cases, e.g. in nbd_read(). This commit is generated by command sed -n '/^Network Block Device (NBD)$/,/^$/{s/^F: //p}' \ MAINTAINERS | \ xargs git ls-files | grep '\.[hc]$' | \ xargs spatch \ --sp-file scripts/coccinelle/errp-guard.cocci \ --macro-file scripts/cocci-macro-file.h \ --in-place --no-show-diff --max-width 80 Reported-by: Kevin Wolf <kwolf@redhat.com> Reported-by: Greg Kurz <groug@kaod.org> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707165037.1026246-8-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and auto-propagated-errp.cocci to errp-guard.cocci. Commit message tweaked again.]
2020-06-10nbd/server: Avoid long error message assertions CVE-2020-10761Eric Blake
Ever since commit 36683283 (v2.8), the server code asserts that error strings sent to the client are well-formed per the protocol by not exceeding the maximum string length of 4096. At the time the server first started sending error messages, the assertion could not be triggered, because messages were completely under our control. However, over the years, we have added latent scenarios where a client could trigger the server to attempt an error message that would include the client's information if it passed other checks first: - requesting NBD_OPT_INFO/GO on an export name that is not present (commit 0cfae925 in v2.12 echoes the name) - requesting NBD_OPT_LIST/SET_META_CONTEXT on an export name that is not present (commit e7b1948d in v2.12 echoes the name) At the time, those were still safe because we flagged names larger than 256 bytes with a different message; but that changed in commit 93676c88 (v4.2) when we raised the name limit to 4096 to match the NBD string limit. (That commit also failed to change the magic number 4096 in nbd_negotiate_send_rep_err to the just-introduced named constant.) So with that commit, long client names appended to server text can now trigger the assertion, and thus be used as a denial of service attack against a server. As a mitigating factor, if the server requires TLS, the client cannot trigger the problematic paths unless it first supplies TLS credentials, and such trusted clients are less likely to try to intentionally crash the server. We may later want to further sanitize the user-supplied strings we place into our error messages, such as scrubbing out control characters, but that is less important to the CVE fix, so it can be a later patch to the new nbd_sanitize_name. Consideration was given to changing the assertion in nbd_negotiate_send_rep_verr to instead merely log a server error and truncate the message, to avoid leaving a latent path that could trigger a future CVE DoS on any new error message. However, this merely complicates the code for something that is already (correctly) flagging coding errors, and now that we are aware of the long message pitfall, we are less likely to introduce such errors in the future, which would make such error handling dead code. Reported-by: Xueqiang Wei <xuwei@redhat.com> CC: qemu-stable@nongnu.org Fixes: https://bugzilla.redhat.com/1843684 CVE-2020-10761 Fixes: 93676c88d7 Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200610163741.3745251-2-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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